By now, you may get the feeling that network management is largely dependent on finding the right module for your device. There is certainly a lot of truth in that logic. Modules provide a way to abstract the interaction between the managed host and the control machine, while it allows you to focus on the logic of your operation. Up to this point, we have seen the major vendors providing a wide range of module support for Cisco, Juniper, and Arista.

Use Cisco Nexus modules as an example, besides specific tasks such as managing the BGP neighbor (nxos_bgp) and the aaa server (nxos_aaa_server). Most vendors also provide ways to run arbitrary show (nxos_config) and configuration commands (nxos_config). This generally covers most of our use cases.

What if the device you are using does not currently have any the modules that you are looking for? In this section, we will look at several ways that you can remedy this situation by writing your own custom module.